Infiltration alloys are used with hard ceramics such as WC or cast carbides in drilling bit and other cutting tool applications. To make such composite materials, a mold is filled with a mixture of ceramic powder and infiltration alloy powder, heated above the liquidus temperature of the infiltration alloy, and cooled to obtain a composite material. Examples of cutting tools comprising such composite materials are disclosed in U.S. Pat. Nos. 5,589,268, 5,733,649 and 5,733,664 which are incorporated herein by reference.
A conventional infiltration alloy comprises copper, manganese, nickel and tin. When such a Cu—Mn—Ni—Sn alloy is used in composite materials that are brazed to steel shanks of drill bits, a twist-off type of failure tends to occur at the interface between the composite material and the steel shank.
Another conventional infiltration alloy comprises copper, manganese, nickel and zinc. The use of such a Cu—Mn—Ni—Zn infiltration alloy may reduce or eliminate the above-noted twist off failure, but may also cause a drop in erosion resistance.
There is a need for a composite material comprising an infiltration alloy with improved erosion resistance and toughness.